/// <summary>
/// Loads TIFF header from stream.
/// </summary>
/// <param name="stream">Fully formatted TIFF image.</param>
/// <returns>Length of header.</returns>
protected override long Load(Stream stream)
{
base.Load(stream);
byte[] temp = stream.ReadBytes(8);
if (!CheckIdentifier(temp))
{
throw new FormatException("Stream is not a recognised TIFF image.");
}
// Change byte order if required.
if (temp[0] == 'M')
{
endianness = MyBitConverter.Endianness.BigEndian;
}
// Header
FirstImageOffset = MyBitConverter.ToUInt32(temp, 4, endianness);
stream.Seek(FirstImageOffset, SeekOrigin.Begin);
var IFD = new ImageFileDirectory(stream, endianness);
Pages = new List <ImageFileDirectory>()
{
IFD
};
// Add mipmaps if they exist
while (IFD.NextIFDOffset != 0)
{
IFD = new ImageFileDirectory(stream, endianness);
Pages.Add(IFD);
}
return(0); // No sensible return value since header is not contiguous (right?)
}
/// <summary>
/// Read sub image header.
/// </summary>
/// <param name="stream">Stream to read local header from.</param>
/// <param name="endianness">Big or little, as defined by TIFF header.</param>
public ImageFileDirectory(Stream stream, MyBitConverter.Endianness endianness) : this()
{
var bytes = stream.ReadBytes(2);
NumberOfEntries = MyBitConverter.ToUInt16(bytes, 0, endianness);
FieldDescriptors = new List <FieldDescriptor>();
for (int i = 0; i < NumberOfEntries; i++)
{
bytes = stream.ReadBytes(12);
FieldDescriptors.Add(new FieldDescriptor(bytes, endianness, stream));
}
}
/// <summary>
/// Read field descriptor from block.
/// A "property" of the image.
/// </summary>
/// <param name="IDBlock">Block containing descriptor, but NOT it's data.</param>
/// <param name="endianness">Big or little endianness defined by TIFF header.</param>
/// <param name="dataStream">Full image stream to read descriptor data from.</param>
public FieldDescriptor(byte[] IDBlock, MyBitConverter.Endianness endianness, Stream dataStream)
{
FieldTag = (FieldTags)MyBitConverter.ToInt16(IDBlock, 0, endianness);
FieldType = (FieldTypes)MyBitConverter.ToInt16(IDBlock, 2, endianness);
FieldLength = MyBitConverter.ToInt32(IDBlock, 4, endianness);
DataOffset = MyBitConverter.ToInt32(IDBlock, 8, endianness);
// Read data indicated by descriptor
long oldOffset = dataStream.Position;
dataStream.Seek(DataOffset, SeekOrigin.Begin);
Data = new byte[FieldLength];
dataStream.Read(Data, 0, FieldLength);
// Reset stream position for next descriptor
dataStream.Seek(oldOffset, SeekOrigin.Begin);
}
/// <summary>
/// Loads TIFF header from stream.
/// </summary>
/// <param name="stream">Fully formatted TIFF image.</param>
/// <returns>Length of header.</returns>
protected override long Load(Stream stream)
{
base.Load(stream);
byte[] temp = stream.ReadBytes(8);
if (!CheckIdentifier(temp))
throw new FormatException("Stream is not a recognised TIFF image.");
// Change byte order if required.
if (temp[0] == 'M')
endianness = MyBitConverter.Endianness.BigEndian;
// Header
FirstImageOffset = MyBitConverter.ToUInt32(temp, 4, endianness);
stream.Seek(FirstImageOffset, SeekOrigin.Begin);
var IFD = new ImageFileDirectory(stream, endianness);
Pages = new List<ImageFileDirectory>() { IFD };
// Add mipmaps if they exist
while (IFD.NextIFDOffset != 0)
{
IFD = new ImageFileDirectory(stream, endianness);
Pages.Add(IFD);
}
return 0; // No sensible return value since header is not contiguous (right?)
}
